Apparatus for producing multiple zone oil and gas wells

ABSTRACT

Two or more oil and gas zones are produced by allowing production from at least one zone to drain down to a common chamber where production from the zones is comingled and lifted to the earth&#39;&#39;s surface. A separate gas vent is provided for each zone to the earth&#39;&#39;s surface.

United States Patent Vencil July 17, 1973 [54] APPARATUS FOR PRODUCINGMULTIPLE 3,003,564 10/1961 Smink 166/313 AND GAS WELLS 1335'???) 111132211"? 1225313 o ges 1 [75] Invent r: Naylan N vencll, Odessa, 3,509,941 51970 Leutwyler c1211.... 166/149 3,552,491 1 1971 Th 1 166 313 [73]Asslgneez Dresser Industries, lnc., Dallas, Tex. 3,559,740 21197 :25???I n 164313 [22] Filed: July 19, 1971 Primary Examiner-James A. Leiapinkl. N 1 3 7 [2]] App 0 6 95 Attorney-Robert W. Mayer, W1l11am E. Johnson,

Jr. et al. v [52] US. Cl. 166/106, 166/189 57 ABSTRACT [51] Int. Cl.E2lb 43/00, E21b 33/122 1 [58] Field of Search 166/115, 114, 313, T orr and gas Zones are P d y allow- 166/189, 105, 106 mg product1on from atleast one zone to dram down to a common chamber where production fromthe zones [56] References Cited is comingled and lifted to the earthssurface. A sepa- UNTED STATES PATENTS rate gas vent 1s provlded for eachzone to the earths surface. R26,319 12/1967 Tamplen 166/115 2,618,33911/1952 Glover 166/114 4 Claims, 3 Drawing Figures Patented July 17,1973 2 Sheets-Sheet 2 M/VLA/ 70? NA YL AN M VEA/C/L APPARATUS FORPRODUCING MULTIPLE ZONE OIL AND GAS WELLS BACKGROUND OF THE INVENTIONThe field of the invention relates to multiple zone wells which requireone or more of the zones to be artificially lifted. This method andapparatus is suitable for wells producing oil, saltwater, fresh water orother liquid with or without natural gas in one or more of the zones.

A prior art device is shown in U. S. Pat. No. 2,6l8,339. This devicediscloses apparatus for comingling multiple zone well production. Theapparatus is arranged in the well so that the upper zone productiontravels down the casing and allows gas entrained in the liquid to breakout and pass to the surface. No provision is made, however, for separatehandling of the lower zone gas. The device does not provide a checkvalve to present high pressure in the lower zone from passing throughthe tool and into the upper zone where such liquid may not berecoverable. Also, the pump intake is positioned above the packer whichis not necessarily a desirable position in the case of a low pressure,low production, lower zone. A further prior art device, shown in U. S.Pat. No. Re 26,319, discloses a flow control device for producingmultiple zone wells which have sufficient drive in the producing zonesto cause the fluid to flow into the well bore where it is meteredthrough predetermined orifices and comingled at a point whereby gas froma higher pressure zone can assist in lifting production from a lowerpressure zone. An additional prior art device, shown in U. S. Pat. No.3,509,941, discloses a confluent production apparatus wherein one zoneor the other or both zones can be produced. Check valves are provided inthe passages from each zone so that flow is prevented between the zonesbut no provision is made for separate handling of gas from the lowerzone nor is the position of the pump intake desirable, because the pumpintake is above the packer between zones and is, therefore, above thelower zone. An additional prior art device, shown in U. S. Pat. No.3,559,740 discloses method and apparatus for use with hydraulic pump andmultiple completion well bores. This patent discloses a separate ventfor the lower zone gas. It also discloses various selector heads whichprovide production from either one or both of the zones and provides forchokes to meter production from the zones. However, none of the priorart devices show or disclose apparatus which adequately drainsproduction from zones in a multiple zone well; wherein one or more zoneshave such low pressure that production is reduced in total or in part byreason of hydrostatic pressure in a column of the liquid in the wellbore being lifted from the zone to a pump intake, and also provideseparate venting of gas from each zone.

It is, therefore, a primary object of this invention to provide amultiple zone producing arrangement which provides for lifting of one ormore low pressure zones.

It is a further object of this invention to provide a multiple zoneproduction apparatus which provides separate venting of the gas fromeach 'zone.

It is a further object of this invention to provide a multiple zoneproduction apparatus which provides for separate measurement of the gasfrom each zone.

It is a further object of this invention to provide a multiple zoneproduction apparatus which conserves hydrocarbons and prevents loss offluid or gas from a high pressure zone into a lower pressure zone in thesame well bore.

SUMMARY OF THE INVENTION These and other objects of this invention arefulfilled, broadly, with a multiple zone producing apparatus and methodwhich provides a chamber for co-mingling fluid from the production zonesat a point below the upper zone. As an additional feature, thecomingling takes place beneath the lower zone.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view partially inelevation and partially in section of a well bore with well casing andapparatus according to this invention which may be used to produce amultiple zone well in accordance with this invention.

FIG. 2 is an alternative embodiment of FIG. 1 showing gas lift means toproduce the liquid from the well.

FIG. 3 is an alternative embodiment of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the preferred embodiment,FIG. 1, casing 10 is shown in a well bore through two producing horizonsl2 and 14. Perforations 16 and 18 in the upper and lower producingzones, respectively, allow production from these zones to flow into thecasing 10. A packer 20 is sealingly engaged with the casing 10 betweenthe perforations. 16 and 18 to isolate the producing zones from eachother. Gas from the upper zone 12 flows into the casing 10 throughperforation 16 and is designated UG. Gas may be dissolved and/orentrained in the upper zone liquid production designated U. Some of theupper zone gas UG can break out of the liquid U and flow upward throughthe casing 10 to be gathered from outlet 22 in the casing at the top ofthe well bore. The volume of U6 gas passing through this outlet can bemeasured and then used for gas lift purposes, sold into a pipeline, orused for another purpose. Production LG from lower zone 14 flowing intocasing 10 through perforation 18 may flow upward into a passage 24 in ahead or barrier portion 26 connected tp packer 20. This gas can thenpass into a tubing string 28 which extends to the top of the well borewhere it may be measured and disposed of in one of the ways mentionedfor the U6 gas. Liquid production U from the upper zone can gravitate orflow downward through passage 30 and head 26 and thence through tubing31 connected to passage 30. A check valve 32 is incorporated in the flowpath for liquid U permitting flow into chamber 34 from the upper zonebut preventing back flow from chamber 34 to passage 30. Lower zoneliquid production L flows into casing 10 through perforation l8 andenters chamber 34 through ball check valve 36 which prevents back flowfrom chamber 34 to perforation 18. A pump 38 is positioned in the tubingstring 40 immediately above chamber 34 where production U and L arecomingled and admitted to the pump intake and lifted to the surface.Pump 38 may alternatively be a plunger pump operated by sucker rods or ahydraulically operated piston pump which has a piston-type motor sectionthat operates a piston-type pump. A bydraulic pump would require anadditional tubular conduit extending from the surface of the well boreto the pump. The additional pipe could be located inside tubular string40 as illustrated in FIG. 2 as tubing string 42 which is illustrated forgas lift purposes. The additional string for the hydraulic pump couldalternately be located beside tubing string 40 in a manner well known bythose with skill in the art.

Referring to FIG. '2, an apparatus used in gas lifting a well accordingto this invention is illustrated. A concentric tubing string 42 is runinside the long tubing string 40 and is used to inject gas through gaslift valves 44 to lift the comingled liquids L and U from chamber 34. Inthis embodiment, gas to lift the comingled fluid is injected at 46 intotubing 40 and is admitted through gas lift valves 44 into the concentrictubing string 42 to lift the comingled fluid through concentric tubingstring 42. A packing arrangement 48 which may be a landing nipple or apacker or other suitable device is used to seal between tubing string 40and tubing string 42 to permit a gas lift arrangement. Otherarrangements for gas lift are well known to those with skill in the artand any one of a number of arrangements may be used to gas lift theliquid from chamber 34.

Referring to FIG. 3, an apparatus used in lifting a well according tothis invention, casing 110 is shown in a well bore through two producinghorizons 1 l2 and 1 14. Perforations 116 and 118 to the upper and lowerproducing zones respectively allow production from these zones to flowinto the casing 1 10. A packer 120 is sealingly engaged to the casing110 between the perforations 116 and 118 to isolate the producing zonesfrom each other. The flow of upper and lower zone gas and liquid isgenerally the same as described hereinbefore except that the head orbarrier portion 126 is simplified to have fewer passages. Lower zone gasLF flows through passage 124 into tubing string 128 connected thereto.Upper z'one liquid production flows through check valve 132 intopassageway 133 in body 126. A tubular string 131 is connected to body126 in alignment with passage 133 to conduct upper zone liquid U tochamber 134. Check valve 136 admits lower zone production liquid L intochamber 134 and prevents back flow therefrom. Tubing string 140 issealingly engaged to head 126 by means of a suitable connection 127.Tubing string 131 is sealingly engaged to tubing string 140 by asuitable connection 135, so that back flow from chamber 134 is preventedinto the upper zone by check valve 132 and back flow from chamber 134 isprevented to lower zone by check valve 136. A suitable plunger pump 138may be used to lift the liquid from chamber 134 through tubing string140. It should be understood that pump 138 may be a hydraulicallyoperated pump. It should also be understood that a gas lift arrangementsimilar to FIG. 2 could be used to lift fluid from chamber 134 throughtubing string 140 to the top of the well bore. These and other means forlifting fluid well known to those skilled in the art may be used inlifting the fluid from chamber 134 according to this invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In dual zone well production apparatus:

a well casing passing through upper and lower producing zones in a wellbore;

said casing having upper and lower openings through which productionfrom said upper and lower zones can flow, respectively, into the wellcasing; barrier means in said casing between said upper and loweropenings;

said barrier means having a longitudinal passage;

a first tubular string extending to the top of the well bore and throughsaid passage in said barrier means;

chamber means below said barrier means, said cham' ber meanscommunicating with said lower 'zone and connected to and communicatingwith said first tubular string for conducting fluid in the lower zone tosaid first tubular string;

a second tubular string extending from above said barrier to below saidbarrier, and surrounding said first tubular string forming an annulustherebetween, said second tubular string communicating with said upperzone and with said chamber for conducting fluid from said upper zone tosaid chamber through said annulus; and

means for lifting fluid from said chamber to the top of the well bore.

2. Apparatus according to claim 1 further comprising:

a second passage insaid barrier means and communicating with said lowerzone; and

a third tubular string communicating with said second passage andextending to the top of the well bore for conducting gas from the lowerzone to the top of the well bore.

3. In dual zone well production apparatus adapted to be set in a wellcasing passing through upper and lower producing zones in a well bore,the casing having upper and lower openings through which production fromthe upper and lower zones can flow, respectively, into the well casing,the apparatus comprising:

barrier means in the casing between the upper and lower openings;

said barrier means laving a longitudinal passage;

a first tubular string extending to the top of the well bore and throughsaid passage in said barrier means;

chamber means below said barrier means, said chamber means communicatingwith said lower zone and connected to and communicating with said firsttubular string;

a second tubular string extending from above said barrier to below saidbarrier and surrounding said first tubular string forming an annulustherebetween, said second tubular string communicating with said upperzone and with said chamber means for conducting fluid from said upperzone to said chamber means through said annulus; and means for liftingfluid from said chamber means to the top of the well bore.

4. Apparatus according to claim 3 further comprising:

a second passage in said barrier means and communicating with said lowerzone; and

a third tubular string communicating with said second passage andextending to the top of the well bore for conducting gas from the lowerzone to the top of the well bore. I!

1. In dual zone well production apparatus: a well casing passing throughupper and lower producing zones in a well bore; said casing having upperand lower openings through which production from said upper and lowerzones can flow, respectively, into the well casing; barrier means insaid casing between said upper and lower openings; said barrier meanshaving a longitudinal passage; a first tubular string extending to thetop of the well bore and through said passage in said barrier means;chamber means below said barrier means, said chamber means communicatingwith said lower zone and connected to and communicating with said firsttubular string for conducting fluid in the lower zone to said firsttubular string; a second tubular string extending from above saidbarrier to below said barrier, and surrounding said first tubular stringforming an annulus therebetween, said second tubular stringcommunicating with said upper zone and with said chamber for conductingfluid from said upper zone to said chamber through said annulus; andmeans for lifting fluid from said chamber to the top of the well bore.2. Apparatus according to claim 1 further comprising: a second passagein said barrier means and communicating with said lower zone; and athird tubular string communicating with said second passage andextending to the top of the well bore for conducting gas from the lowerzone to the top of the well bore.
 3. In dual zone well productionapparatus adapted to be set in a well casing passing through upper andlower producing zones in a well bore, the casing having upper and loweropenings through which production from the upper and lower zones canflow, respectively, into the well casing, the apparatus comprising:barrier means in the casing between the upper and lower openings; saidbarrier means laving a longitudinal passage; a first tubular stringextending to the top of the well bore and through said passage in saidbarrier means; chamber means below said barrier means, said chambermeans communicating with said lower zone and connected to andcommunicating with said first tubular string; a second tubular stringextending from above said barrier to below said barrier and surroundingsaid first tubular string forming an annulus therebetween, said secondtubular string communicating with said upper zone and with said chambermeans for conducting fluid from said upper zone to said chamber meansthrough said annulus; and means for lifting fluid from said chambermeans to the top of the well bore.
 4. Apparatus according to claim 3further comprising: a second passage in said barrier means andcommunicating with said lower zone; and a third tubular stringcommunicating with said second passage and extending to the top of thewell bore for conducting gas from the lower zone to the top of the wellbore.